Optical frequency tripling with improved suppression and sideband selection

Journal Article, Impact factor:3.749A novel optical dispersion tolerant millimetre-wave radio-over-fibre system using optical frequency tripling technique with enhanced and selectable sideband suppression is demonstrated. The implementation utilises cascaded optical modulators to achieve either an optical single sideband (OSSB) or double sideband-suppressed carrier (DSB-SC) signal with high sideband suppression. Our analysis and simulation results indicate that the achievable suppression ratio of this configuration is only limited by other system factors such as optical noise and drifting of the operational conditions. The OSSB transmission system performance is assessed experimentally by the transport of 4 WiMax channels modulating a 10 GHz optical upconverted RF carrier as well as for optical frequency doubling and tripling. The 10 GHz and tripled carrier at 30 GHz are dispersion tolerant resulting both in an average relative constellation error (RCE) of -28.7 dB after 40 km of fibre. (C)2011 Optical Society of AmericaFundação para a Ciência e Tecnologi

Optical Strategies for Generating and Transmitting Signals in OFDM-RoF Systems

Part 17: TelecommunicationsInternational audienceRadio-over-Fiber (RoF) systems which act as backbone networks are very promising means of reducing overall costs of 60 GHz WPANs, as well leading to networks with limited intercellular interference. The main objective of this paper is to compare the performance of two systems that generate Optical Single Side Band (OSSB) OFDM signals at the mm-wave band with and without optical up-conversion. Both systems use a DD-MZM: one is a standard model, whereas the other is a DD-MZM cascaded with a phase modulator (PM). The comparative study presented here also includes practical impairments such as the finite extinction ratio of DD-MZMs

Análise de sistemas de comunicação óptica com multiplexagem de subportadora e transmissão em banda lateral única

Tese dout., Engenharia Electrónica e Computação, Universidade do Algarve, 2005The transmission of optical single sideband signal with subcarrier multiplexing is a very promising technique for future telecommunications systems. This is an optical technology which combines optical single sideband (OSSB) modulation advantages with the subcarrier multiplexing (SCM) characteristics of simplicity and flexibility. This thesis analyses OSSB/SCM systems performance with direct detection and electrical coherent demodulation and compares its performance when different modulation schemes are applied to the individual data channels. This analysis is extended to systems using optical the in-line amplifiers. Analytical methods are developed to evaluate the degradation of performance of these system caused by laser intensity noise at fiber output, intermodulation distortion, optical amplifier noise and nonlinear four-wave mixing effect from optical fibers. Special attention is given to the power suppression ratio of the optical carrier since it is found to be an important parameter on the system performance. The obtained results show that the system performance has a great sensitivity to the system parameters. This system behaviour requires a careful choice of system parameters in order to achieve optimum system performance.Fundação para a Ciência e Tecnologia (FCT

Transmission Performance of mm-Waves on Radio over Fiber Systems: Dispersion and Intermodulation Issues

International audienceNext generation wireless networks must provide high broadband access, which can be achieved by combining the fiber optics and wireless technologies. In this paper we analyze a mm-wave radio over fiber (RoF) optical access network architecture, combining radio subcarrier multiplexing techniques to improve system efficiency with fiber dispersion mitigation provided by optical single sideband modulation techniques. Our results show the system degradation introduced by the fiber link, namely fiber dispersion and intermodulation effects